Semiconductor device having a controllable voltage supply

Abstract

A semiconductor device includes a nonvolatile memory cell and a current detecting type sense amplifier for detecting a current flowing through a data line into the memory cell. The semiconductor device is further provided with an element for outputting a first voltage detecting signal when a detected supply voltage exceeds a set value and outputting a second voltage detecting signal when the detected supply voltage does not exceed the set value. The sense amplifier includes an element for switching a dependent characteristic of a level sensing current upon the supply voltage to be a higher response to the first voltage detecting signal. Thus, error reading of a data from the memory cell, which can be otherwise caused under application of a low supply voltage, can be avoided.

We claim: 
     
       1. A semiconductor device comprising: a memory cell;   a signal line connected to the memory cell;   voltage supplying means for supplying a supply voltage to the signal line;   supply voltage detecting means connected to the voltage supply means, for outputting a first voltage detecting signal when the supply voltage exceeds a set value and outputting a second voltage detecting signal when the supply voltage does not exceed the set value; and   controlling means for setting a potential of the signal line equal to the supply voltage when the first voltage detecting signal is received, while boosting a potential of the signal line higher than the supply voltage when the second voltage detecting signal is received.   
     
     
       2. The semiconductor device of claim 1, wherein the signal line is a word line of the memory cell. 
     
     
       3. The semiconductor device of claim 1, wherein the signal line is a data line of the memory cell. 
     
     
       4. A semiconductor device comprising: a memory cell;   a signal line connected to the memory cell;   voltage supplying means for supplying a supply voltage to the signal line;   supply voltage detecting means connected to the voltage supplying means, for outputting a first voltage detecting signal when the supply voltage exceeds a set value and outputting a second voltage detecting signal when the supply voltage does not exceed the set value;   controlling means for setting a potential of the signal line equal to the supply voltage when the first voltage detecting signal is received, while boosting a potential of the signal line higher than the supply voltage when the second voltage detecting signal is received; and   limiting means for limiting the potential of the signal line to be set by the controlling means to any potential that is higher than the supply voltage by a given value.   
     
     
       5. A semiconductor device of claim 4, wherein the signal is a word line of the memory cell. 
     
     
       6. A semiconductor device of claim 4, wherein the signal is a data line of the memory cell.